Cold Root Rolling Blog

Cold Root Rolling: Process, Applications & Benefits

Posted by CJWinter on Aug 27, 2019 9:16:58 AM

For almost 60 years, CJWinter has been one of the world’s leading providers of thread rolls and thread rolling tools. These products find application in traditional thread-rolling operation, as well as specialty ones, such as cold root rolling operations.

Cold root rolling is an innovative process that strengthens pipeline connections, minimizing the risk of costly equipment failure to safeguard your employees and facilities. The following guide focuses on cold root rolling, outlining the basics of the process, its uses and applications, and its benefits.

What Is Cold Root Rolling?

The cold root rolling process strengthens rotary shouldered connections. CJWinter’s specialized cold root rolling tools facilitate this process by burnishing the root radius of severed threads and cold forming the material to increase its deformation resistance, improving both the surface finish and the root substance’s strength. The hardened roll of these tools first applies pressure to the surface of the thread and then penetrates it, displacing the thread material to restructure the steel grain’s crystalline lattice.

At CJWinter, our advanced tools simplify this cold root rolling process by being intuitive and compatible with almost any control mechanism, including popular lathes by Fanuc, Weiler, and Mazak. They also function without the need for an external power device and are equipped with an Error Proof Loading (EPL) System for easy setup.

Uses and Applications

Cold root rolling most commonly finds application in offshore drill string assemblies. However, on-shore drill operators have recently begun to recognize the benefits of cold root rolling, leading to its use in extended-reach drilling, multilateral well, and horizontal well operations. Regardless of whether the application is on-shore or offshore, the process can strengthen any threaded connection that experiences significant stress.

Using our extensive industry experience, we developed customized tooling for use in the petroleum industry. In doing so, we’ve become the only cold root rolling provider to offer a self-contained, commercially available tool that complies with:

  • ANSI/API Specification 7.2:2008
  • ISO 10424-2:2007, in accordance with NS-1 cold root rolling procedures
  • DS-1 Third Edition, Volume 3.33.6

Benefits of Cold Root Rolling

The core benefit of cold root rolling is that it strengthens drill string connections, helping them to perform at their best for longer. In some studies, cold root rolled joints demonstrated a joint-life three to five times that of comparable untreated connections.

Other benefits of cold root rolling include:

  • Greater strength. The burnishing stage of the cold root rolling process alters the steel material on an atomic level, changing the crystalline structure to one that is dislocated and interlocked. The resulting structure is far stronger and better able to resist cracking.
  • Higher stress resistance. A rolled joint distributes thread root stress more effectively than an untreated one. This characteristic is because the process creates sufficient residual compressive stress to offset the tensile stress generated by normal operations. 
  • Better corrosion resistance. Scratches and other surface imperfections increase the risk of chemical corrosion, especially in drilling environments that harbor many hazardous chemicals. Cold root rolling can prevent corrosion by smoothing away scratches, reducing the impact of chemicals on critical structural components.
  • Lower repair costs, less frequent repairs. The increased strength and durability afforded by the cold root rolling process minimizes the risk of connection failure, reducing the need for and incidence of costly repairs.

These benefits and more are easy to achieve, given the right equipment. CJWinter’s cold root rolling tools are carefully engineered to maximize versatility and efficiency. With features such as an asymmetrical EPL system and a 1:1 pressure ratio conversion, our devices are some of the most intuitive on the market, making adoption and integration safe and simple.

Contact the Experts at CJWinter

According to industrial reports, a single faulty connection can lead to losses of $250,000 a day for offshore drilling operations. Thankfully, these losses are easy to avoid with our state-of-the-art cold root rolling equipment.

To learn more about the cold root rolling process and our tool offerings, contact us or request a quote from the cold root rolling experts at CJWinter today.

Cold Root Rolling- Process, Applications & Benefits


Topics: Cold Root Rolling